Module org.hdfgroup.object

Package hdf.object.fits

Class FitsDatatype

Object

hdf.object.HObject

hdf.object.Datatype

hdf.object.fits.FitsDatatype

All Implemented Interfaces:

MetaDataContainer, Serializable

public class FitsDatatype
extends Datatype

Datatype encapsulates information of a datatype. Information includes the class, size, endian of a datatype.

Version:

1.1 9/4/2007

Author:

Peter X. Cao

See Also:

Serialized Form

Field Summary

Fields inherited from class hdf.object.Datatype

arrayDims, baseType, CLASS_ARRAY, CLASS_BITFIELD, CLASS_CHAR, CLASS_COMPOUND, CLASS_ENUM, CLASS_FLOAT, CLASS_INTEGER, CLASS_NO_CLASS, CLASS_OPAQUE, CLASS_REFERENCE, CLASS_STRING, CLASS_TIME, CLASS_VLEN, compoundMemberNames, compoundMemberOffsets, compoundMemberTypes, datatypeClass, datatypeDescription, datatypeOrder, datatypeSign, datatypeSize, enumMembers, isNamed, isVariableStr, isVLEN, NATIVE, NSGN, ORDER_BE, ORDER_LE, ORDER_NONE, ORDER_VAX, SIGN_2, SIGN_NONE

Fields inherited from class hdf.object.HObject

fileFormat, linkTargetObjName, oid, SEPARATOR

Constructor Summary

Constructors

Constructor	Description
FitsDatatype(int tclass, int tsize, int torder, int tsign)	Create an Datatype with specified class, size, byte order and sign.
FitsDatatype(long theType)	Create a Datatype with a given fits native datatype.

Method Summary

Modifier and Type	Method	Description
static Object	allocateArray(long dtype, int size)	Allocate an one-dimensional array of byte, short, int, long, float, double, or String to store data retrieved from an fits file based on the given fits datatype and dimension sizes.
void	close(long id)	Closes a datatype identifier.
long	createNative()	Converts the datatype object to a native datatype.
void	fromNative()	Translate fits datatype identifier into FitsDatatype.
void	fromNative(long dtype)	Translate fits datatype identifier into FitsDatatype.
String	getDescription()	Returns a short text description of this datatype.
List	getMetadata(int... attrPropList)
boolean	hasAttribute()	Check if the object has any attributes attached.
boolean	isText()
boolean	isUnsigned()	Checks if this datatype is unsigned.

Methods inherited from class hdf.object.Datatype

getArrayDims, getCompoundMemberNames, getCompoundMemberTypes, getDatatypeBase, getDatatypeClass, getDatatypeOrder, getDatatypeSign, getDatatypeSize, getEnumMembers, getEnumMembersAsString, getMetadata, isArray, isBitField, isChar, isCompound, isEnum, isFloat, isInteger, isNamed, isOpaque, isRef, isString, isVarStr, isVLEN, open, removeMetadata, setEnumMembers, toString, updateMetadata, writeMetadata

Methods inherited from class hdf.object.HObject

createFullname, debug, equals, equals, equalsOID, getFID, getFile, getFileFormat, getFullName, getLinkTargetObjName, getName, getOID, getPath, hashCode, setFullname, setLinkTargetObjName, setName, setPath

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

FitsDatatype

public FitsDatatype(int tclass,
int tsize,
int torder,
int tsign)
             throws Exception

Create an Datatype with specified class, size, byte order and sign. The following list a few example of how to create a Datatype.

1. to create unsigned native integer
   FitsDatatype type = new H5Dataype(Datatype.CLASS_INTEGER, Datatype.NATIVE, Datatype.NATIVE, Datatype.SIGN_NONE);
2. to create 16-bit signed integer with big endian
   FitsDatatype type = new H5Dataype(Datatype.CLASS_INTEGER, 2, Datatype.ORDER_BE, Datatype.NATIVE);
3. to create native float
   FitsDatatype type = new H5Dataype(Datatype.CLASS_FLOAT, Datatype.NATIVE, Datatype.NATIVE, Datatype.NATIVE);
4. to create 64-bit double
   FitsDatatype type = new H5Dataype(Datatype.CLASS_FLOAT, 8, Datatype.NATIVE, Datatype.NATIVE);

Parameters:

tclass - the class of the datatype.

tsize - the size of the datatype in bytes.

torder - the order of the datatype.

tsign - the sign of the datatype.

Throws:

Exception - if there is an error

FitsDatatype

public FitsDatatype(long theType)
             throws Exception

Create a Datatype with a given fits native datatype.

Parameters:

theType - the fits native datatype.

Throws:

Exception - if there is an error

Method Details

hasAttribute

public boolean hasAttribute()

Description copied from interface: MetaDataContainer

Check if the object has any attributes attached.

Returns:

true if it has any attributes, false otherwise.

allocateArray

public static Object allocateArray(long dtype,
int size)
                            throws OutOfMemoryError

Allocate an one-dimensional array of byte, short, int, long, float, double, or String to store data retrieved from an fits file based on the given fits datatype and dimension sizes.

Parameters:

dtype - the fits datatype.

size - the total size of the array.

Returns:

the array object if successful and null otherwise.

Throws:

OutOfMemoryError

fromNative

public void fromNative()

Translate fits datatype identifier into FitsDatatype.

fromNative

public void fromNative(long dtype)

Translate fits datatype identifier into FitsDatatype.

Specified by:

fromNative in class Datatype

Parameters:

dtype - the fits native datatype.

getDescription

public String getDescription()

Description copied from class: Datatype

Returns a short text description of this datatype.

Overrides:

getDescription in class Datatype

Returns:

a short text description of this datatype

isText

public boolean isText()

Specified by:

isText in class Datatype

isUnsigned

public boolean isUnsigned()

Description copied from class: Datatype

Checks if this datatype is unsigned.

Overrides:

isUnsigned in class Datatype

Returns:

true if the datatype is unsigned; otherwise, returns false.

createNative

public long createNative()

Description copied from class: Datatype

Converts the datatype object to a native datatype. Subclasses must implement it so that this datatype will be converted accordingly. Use close() to close the native identifier; otherwise, the datatype will be left open.

For example, a HDF5 datatype created from

 H5Dataype dtype = new H5Datatype(CLASS_INTEGER, 4, NATIVE, SIGN_NONE);
 int tid = dtype.createNative();
 

The "tid" will be the HDF5 datatype id of a 64-bit unsigned integer, which is equivalent to

 int tid = H5.H5Tcopy(HDF5Constants.H5T_NATIVE_UNINT32);
 

Specified by:

createNative in class Datatype

Returns:

the identifier of the native datatype.

close

public void close(long id)

Description copied from class: Datatype

Closes a datatype identifier.

Sub-classes must replace this default implementation.

Specified by:

close in class Datatype

Parameters:

id - the datatype identifier to close.

getMetadata

public List getMetadata(int... attrPropList)
                 throws Exception

Throws:

Exception